proxy_cache.c

apache简化版

}

/*
 * Having read the response from the client, decide what to do
 * If the response is not cachable, then delete any previously cached
 * response, and copy data from remote server to client.
 * Functions:
 *  parse dates
 *  check for an uncachable response
 *  calculate an expiry date, if one is not provided
 *  if the remote file has not been modified, then return the document
 *  from the cache, maybe updating the header line
 *  otherwise, delete the old cached file and open a new temporary file
 */
int ap_proxy_cache_update(cache_req *c, table *resp_hdrs,
		       const int is_HTTP1, int nocache)
{
#ifdef ULTRIX_BRAIN_DEATH
  extern char *mktemp(char *template);
#endif 
    request_rec *r = c->req;
    char *p;
    int i;
    const char *expire, *lmods, *dates, *clen;
    time_t expc, date, lmod, now;
    char buff[46];
    void *sconf = r->server->module_config;
    proxy_server_conf *conf =
    (proxy_server_conf *) ap_get_module_config(sconf, &proxy_module);
    const long int zero = 0L;

    c->tempfile = NULL;

/* we've received the response */
/* read expiry date; if a bad date, then leave it so the client can
 * read it
 */
    expire = ap_table_get(resp_hdrs, "Expires");
    if (expire != NULL)
	expc = ap_parseHTTPdate(expire);
    else
	expc = BAD_DATE;

/*
 * read the last-modified date; if the date is bad, then delete it
 */
    lmods = ap_table_get(resp_hdrs, "Last-Modified");
    if (lmods != NULL) {
	lmod = ap_parseHTTPdate(lmods);
	if (lmod == BAD_DATE) {
/* kill last modified date */
	    lmods = NULL;
	}
    }
    else
	lmod = BAD_DATE;

/*
 * what responses should we not cache?
 * Unknown status responses and those known to be uncacheable
 * 304 HTTP_NOT_MODIFIED response when we have no valid cache file, or
 * 200 HTTP_OK response from HTTP/1.0 and up without a Last-Modified header, or
 * HEAD requests, or
 * requests with an Authorization header, or
 * protocol requests nocache (e.g. ftp with user/password)
 */
/* @@@ XXX FIXME: is the test "r->status != HTTP_MOVED_PERMANENTLY" corerct?
 * or shouldn't it be "ap_is_HTTP_REDIRECT(r->status)" ? -MnKr */
    if ((r->status != HTTP_OK && r->status != HTTP_MOVED_PERMANENTLY && r->status != HTTP_NOT_MODIFIED) ||
	(expire != NULL && expc == BAD_DATE) ||
	(r->status == HTTP_NOT_MODIFIED && (c == NULL || c->fp == NULL)) ||
	(r->status == HTTP_OK && lmods == NULL && is_HTTP1) ||
	r->header_only ||
	ap_table_get(r->headers_in, "Authorization") != NULL ||
	nocache) {
	Explain1("Response is not cacheable, unlinking %s", c->filename);
/* close the file */
	if (c->fp != NULL) {
	    ap_pclosef(r->pool, c->fp->fd);
	    c->fp = NULL;
	}
/* delete the previously cached file */
        if (c->filename)
            unlink(c->filename);
	return DECLINED;	/* send data to client but not cache */
    }

/* otherwise, we are going to cache the response */
/*
 * Read the date. Generate one if one is not supplied
 */
    dates = ap_table_get(resp_hdrs, "Date");
    if (dates != NULL)
	date = ap_parseHTTPdate(dates);
    else
	date = BAD_DATE;

    now = time(NULL);

    if (date == BAD_DATE) {	/* No, or bad date */
/* no date header! */
/* add one; N.B. use the time _now_ rather than when we were checking the cache
 */
	date = now;
	dates = ap_gm_timestr_822(r->pool, now);
	ap_table_set(resp_hdrs, "Date", dates);
	Explain0("Added date header");
    }

/* check last-modified date */
    if (lmod != BAD_DATE && lmod > date)
/* if its in the future, then replace by date */
    {
	lmod = date;
	lmods = dates;
	Explain0("Last modified is in the future, replacing with now");
    }
/* if the response did not contain the header, then use the cached version */
    if (lmod == BAD_DATE && c->fp != NULL) {
	lmod = c->lmod;
	Explain0("Reusing cached last modified");
    }

/* we now need to calculate the expire data for the object. */
    if (expire == NULL && c->fp != NULL) {	/* no expiry data sent in response */
	expire = ap_table_get(c->hdrs, "Expires");
	if (expire != NULL)
	    expc = ap_parseHTTPdate(expire);
    }
/* so we now have the expiry date */
/* if no expiry date then
 *   if lastmod
 *      expiry date = now + min((date - lastmod) * factor, maxexpire)
 *   else
 *      expire date = now + defaultexpire
 */
    Explain1("Expiry date is %ld", expc);
    if (expc == BAD_DATE) {
	if (lmod != BAD_DATE) {
	    double x = (double) (date - lmod) * conf->cache.lmfactor;
	    double maxex = conf->cache.maxexpire;
	    if (x > maxex)
		x = maxex;
	    expc = now + (int) x;
	}
	else
	    expc = now + conf->cache.defaultexpire;
	Explain1("Expiry date calculated %ld", expc);
    }

/* get the content-length header */
    clen = ap_table_get(resp_hdrs, "Content-Length");
    if (clen == NULL)
	c->len = -1;
    else
	c->len = atoi(clen);

    ap_proxy_sec2hex(date, buff);
    buff[8] = ' ';
    ap_proxy_sec2hex(lmod, buff + 9);
    buff[17] = ' ';
    ap_proxy_sec2hex(expc, buff + 18);
    buff[26] = ' ';
    ap_proxy_sec2hex(c->version++, buff + 27);
    buff[35] = ' ';
    ap_proxy_sec2hex(c->len, buff + 36);
    buff[44] = '\n';
    buff[45] = '\0';

/* if file not modified */
    if (r->status == HTTP_NOT_MODIFIED) {
	if (c->ims != BAD_DATE && lmod != BAD_DATE && lmod <= c->ims) {
/* set any changed headers somehow */
/* update dates and version, but not content-length */
	    if (lmod != c->lmod || expc != c->expire || date != c->date) {
		off_t curpos = lseek(c->fp->fd, 0, SEEK_SET);
		if (curpos == -1)
		    ap_log_rerror(APLOG_MARK, APLOG_ERR, r,
				 "proxy: error seeking on cache file %s",
				 c->filename);
		else if (write(c->fp->fd, buff, 35) == -1)
		    ap_log_rerror(APLOG_MARK, APLOG_ERR, r,
				 "proxy: error updating cache file %s",
				 c->filename);
	    }
	    ap_pclosef(r->pool, c->fp->fd);
	    Explain0("Remote document not modified, use local copy");
	    /* CHECKME: Is this right? Shouldn't we check IMS again here? */
	    return HTTP_NOT_MODIFIED;
	}
	else {
/* return the whole document */
	    Explain0("Remote document updated, sending");
	    r->status_line = strchr(c->resp_line, ' ') + 1;
	    r->status = c->status;
	    if (!r->assbackwards) {
		ap_soft_timeout("proxy send headers", r);
		ap_proxy_send_headers(r, c->resp_line, c->hdrs);
		ap_kill_timeout(r);
	    }
	    ap_bsetopt(r->connection->client, BO_BYTECT, &zero);
	    r->sent_bodyct = 1;
	    if (!r->header_only)
		ap_proxy_send_fb(c->fp, r, NULL);
/* set any changed headers somehow */
/* update dates and version, but not content-length */
	    if (lmod != c->lmod || expc != c->expire || date != c->date) {
		off_t curpos = lseek(c->fp->fd, 0, SEEK_SET);

		if (curpos == -1)
		    ap_log_rerror(APLOG_MARK, APLOG_ERR, r,
				 "proxy: error seeking on cache file %s",
				 c->filename);
		else if (write(c->fp->fd, buff, 35) == -1)
		    ap_log_rerror(APLOG_MARK, APLOG_ERR, r,
				 "proxy: error updating cache file %s",
				 c->filename);
	    }
	    ap_pclosef(r->pool, c->fp->fd);
	    return OK;
	}
    }
/* new or modified file */
    if (c->fp != NULL) {
	ap_pclosef(r->pool, c->fp->fd);
	c->fp->fd = -1;
    }
    c->version = 0;
    ap_proxy_sec2hex(0, buff + 27);
    buff[35] = ' ';

/* open temporary file */
#define TMPFILESTR	"/tmpXXXXXX"
    if (conf->cache.root == NULL)
	return DECLINED;
    c->tempfile = ap_palloc(r->pool, strlen(conf->cache.root) + sizeof(TMPFILESTR));
    strcpy(c->tempfile, conf->cache.root);
    strcat(c->tempfile, TMPFILESTR);
#undef TMPFILESTR
    p = mktemp(c->tempfile);
    if (p == NULL)
	return DECLINED;

    Explain1("Create temporary file %s", c->tempfile);

    i = open(c->tempfile, O_WRONLY | O_CREAT | O_EXCL | O_BINARY, 0622);
    if (i == -1) {
	ap_log_rerror(APLOG_MARK, APLOG_ERR, r,
		     "proxy: error creating cache file %s",
		     c->tempfile);
	return DECLINED;
    }
    ap_note_cleanups_for_fd(r->pool, i);
    c->fp = ap_bcreate(r->pool, B_WR);
    ap_bpushfd(c->fp, -1, i);

    if (ap_bvputs(c->fp, buff, "X-URL: ", c->url, "\n", NULL) == -1) {
	ap_log_rerror(APLOG_MARK, APLOG_ERR, r,
		     "proxy: error writing cache file(%s)", c->tempfile);
	ap_pclosef(r->pool, c->fp->fd);
	unlink(c->tempfile);
	c->fp = NULL;
    }
    return DECLINED;
}

void ap_proxy_cache_tidy(cache_req *c)
{
    server_rec *s;
    long int bc;

    if (c == NULL || c->fp == NULL)
	return;

    s = c->req->server;

/* don't care how much was sent, but rather how much was written to cache
    ap_bgetopt(c->req->connection->client, BO_BYTECT, &bc);
 */
    bc = c->written;

    if (c->len != -1) {
/* file lengths don't match; don't cache it */
	if (bc != c->len) {
	    ap_pclosef(c->req->pool, c->fp->fd);	/* no need to flush */
	    unlink(c->tempfile);
	    return;
	}
    }
/* don't care if aborted, cache it if fully retrieved from host!
    else if (c->req->connection->aborted) {
	ap_pclosef(c->req->pool, c->fp->fd);	/ no need to flush /
	unlink(c->tempfile);
	return;
    }
*/
    else {
/* update content-length of file */
	char buff[9];
	off_t curpos;

	c->len = bc;
	ap_bflush(c->fp);
	ap_proxy_sec2hex(c->len, buff);
	curpos = lseek(c->fp->fd, 36, SEEK_SET);
	if (curpos == -1)
	    ap_log_error(APLOG_MARK, APLOG_ERR, s,
			 "proxy: error seeking on cache file %s", c->tempfile);
	else if (write(c->fp->fd, buff, 8) == -1)
	    ap_log_error(APLOG_MARK, APLOG_ERR, s,
			 "proxy: error updating cache file %s", c->tempfile);
    }

    if (ap_bflush(c->fp) == -1) {
	ap_log_error(APLOG_MARK, APLOG_ERR, s,
		     "proxy: error writing to cache file %s",
		     c->tempfile);
	ap_pclosef(c->req->pool, c->fp->fd);
	unlink(c->tempfile);
	return;
    }

    if (ap_pclosef(c->req->pool, c->fp->fd) == -1) {
	ap_log_error(APLOG_MARK, APLOG_ERR, s,
		     "proxy: error closing cache file %s", c->tempfile);
	unlink(c->tempfile);
	return;
    }

    if (unlink(c->filename) == -1 && errno != ENOENT) {
	ap_log_error(APLOG_MARK, APLOG_ERR, s,
		     "proxy: error deleting old cache file %s",
		     c->tempfile);
    }
    else {
	char *p;
	proxy_server_conf *conf =
	(proxy_server_conf *) ap_get_module_config(s->module_config, &proxy_module);

	for (p = c->filename + strlen(conf->cache.root) + 1;;) {
	    p = strchr(p, '/');
	    if (!p)
		break;
	    *p = '\0';
#ifdef WIN32
	    if (mkdir(c->filename) < 0 && errno != EEXIST)
#else
	    if (mkdir(c->filename, S_IREAD | S_IWRITE | S_IEXEC) < 0 && errno != EEXIST)
#endif /* WIN32 */
		ap_log_error(APLOG_MARK, APLOG_ERR, s,
			     "proxy: error creating cache directory %s",
			     c->filename);
	    *p = '/';
	    ++p;
	}
#if defined(OS2) || defined(WIN32)
	/* Under OS/2 use rename. */
	if (rename(c->tempfile, c->filename) == -1)
	    ap_log_error(APLOG_MARK, APLOG_ERR, s,
			 "proxy: error renaming cache file %s to %s",
			 c->tempfile, c->filename);
    }
#else

	if (link(c->tempfile, c->filename) == -1)
	    ap_log_error(APLOG_MARK, APLOG_ERR, s,
			 "proxy: error linking cache file %s to %s",
			 c->tempfile, c->filename);
    }

    if (unlink(c->tempfile) == -1)
	ap_log_error(APLOG_MARK, APLOG_ERR, s,
		     "proxy: error deleting temp file %s", c->tempfile);
#endif

}